• Category
  • Length Range
    20.5-48.5 µm
  • Width Range
    5.4-8.4 µm
  • Striae in 10 µm
  • Reported As
    Navicula cincta var. heufleri (Hustedt 1930, p. 298, Fig. 511)
    Navicula heufleri (Patrick and Reimer, p. 515, Plate 49, Fig. 6)
    Navicula walkeri (Patrick and Freese, p. 217, Plate 2, Fig. 12)



Valves are lanceolate to elliptic-lanceolate with narrowly rounded apices. The axial area is very narrow and linear. The central area is highly variable in shape and size, from elliptic to transversely rectangular, and often asymmetric. The raphe is filiform with tear-shaped proximal raphe ends that are deflected slightly to one side. The lineate striae are radiate, becoming convergent at the apices. Striae are unevenly spaced around the central area. The areolae are easily observed under LM and number 28-34 in 10 µm.


Navicula eidrigiana is an uncommon resident of brackish springs and small streams on the Northwestern Great Plains. It typically prefers waters with a higher electrolyte content than Navicula libonensis. Some of the specimens on this page come from Iron Spring on the Custer National Forest in Carter County, Montana (photo below). Iron Spring has a pH of 8.32, conductivity of 2740 µS/cm, and temperature of 22.2 C.

Iron  Spring 2
Credit: Loren Bahls
Iron Spring, Carter County, Montana: home of Cymbella hantzschiana

Original Description

  • Author
    Carter 1979
  • Length Range
    20-55 µm
  • Width
    6-8 µm
  • Striae in 10µm

Original Images

Navicula Eidrigiana Origimag1
Navicula Eidrigiana Origimag2
Navicula Eidrigiana Origdesc

Cite This Page

Bahls, L. (2016). Navicula eidrigiana. In Diatoms of North America. Retrieved October 20, 2020, from https://diatoms.org/species/navicula_eidrigiana


The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Navicula eidrigiana from all the stream reaches where it was present. Note that the relative abundance scale is the same on each plot. Explanation of each environmental variable and units are as follows:

ELEVATION = stream reach elevation (meters)
STRAHLER = distribution plot of the Strahler Stream Order
SLOPE = stream reach gradient (degrees)
W1_HALL = an index that is a measure of streamside (riparian) human activity that ranges from 0 - 10, with a value of 0 indicating of minimal disturbance to a value of 10 indicating severe disturbance.
PHSTVL = pH measured in a sealed syringe sample (pH units)
log_COND = log concentration of specific conductivity (µS/cm)
log_PTL = log concentration of total phosphorus (µg/L)
log_NO3 = log concentration of nitrate (µeq/L)
log_DOC = log concentration of dissolved organic carbon (mg/L)
log_SIO2 = log concentration of silicon (mg/L)
log_NA = log concentration of sodium (µeq/L)
log_HCO3 = log concentration of the bicarbonate ion (µeq/L)
EMBED = percent of the stream substrate that is embedded by sand and fine sediment
log_TURBIDITY = log of turbidity, a measure of cloudiness of water, in nephelometric turbidity units (NTU).
DISTOT = an index of total human disturbance in the watershed that ranges from 1 - 100, with a value of 0 indicating of minimal disturbance to a value of 100 indicating severe disturbance.